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OCHT Term II > ANATOMY - Term Test 6 (Endocrine & Urinary) > Flashcards

ANATOMY - Term Test 6 (Endocrine & Urinary) Flashcards

1
Q

The endocrine system and nervous system both function to do what?

A

maintain stability of the internal environment

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2
Q

The endocrine system and nervous system together are called ____________ and perform similar general functions in the body which are:

A

neuroendocrine system

Functions: communication, integration, and control

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3
Q

How does the nervous system perform regulatory functions (i.e. by what means does it work on the body)?

A

neurons secrete NT molecules to signal nearby cells that have the appropriate receptor molecules (post-synaptic cells)

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4
Q

How does the endocrine system perform its regulatory functions (i.e. by what means)?

A

secreting cells in the endocrine system send hormone molecules in the bloodstream to target cells throughout the body via lock and key mechanism (organs/tissues that endocrine system acts on and has target cells in it are called target organs/tissues)

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5
Q

Signal transduction

A
  • aka cell signaling; a process where a chemical signal is transmitted through the cell by appropriate receptors
  • each cellular change is caused by a different hormone-receptor interaction causing chemical reactions within the cell
  • can initiate synthesis of new proteins, activate/inactive certain enzymes, open/close specific ion channels in the plasma membrane
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6
Q

Compare the two: Neurotransmitters (NT) and hormones

1) Distance traveled
2) Short or long-lived
c) Organs they have effects on

A

1) Distance traveled: NT travel short distances across a synapse; hormones diffuse into blood and can be carried all throughout the body where blood reaches so everywhere

2) Short or long-lived effects: NT are rapid and short-lived; hormones’ effects are slower and last longer

3) Target Organs: Nervous system can only directly control muscles and glands that are innervated with efferent fibers; endocrine system can regulate most cells in the body

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7
Q

Regulatory feedback loops in the endocrine system are called:

Regulatory feedback loops in the nervous system are called:

A

endocrine reflexes

nervous reflexes

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8
Q

Cells that secrete the chemical messenger in endocrine system vs nervous system

A

Endocrine system: glandular epithelial cells or neurosecretory cells (modified neurons)

Nervous system: neurons

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9
Q

Location of receptor in the effector cell in endocrine system vs nervous system

A

Endocrine system: receptors are on the plasma membrane or within the cell

Nervous system: receptors are on the plasma membrane

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10
Q

Endocrine vs exocrine glands

A

Endocrine glands: secrete hormones directly into the blood - DUCTLESS glands

Exocrine glands: secrete their products into ducts

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11
Q

Neurosecretory cells/tissue

A

modified neurons that secrete chemical messengers that diffuse into the bloodstream rather than across a synapse (that’s why some chemical messengers can be a hormone AND a neurotransmittor, but would be called a hormone such as NE)

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12
Q

Major endocrine glands and their locations

A

1) hypothalamus - cranial cavity (brain)
2) pituitary - cranial cavity
3) pineal - cranial cavity (brain)
4) thyroid - neck
5) parathyroids (on posterior surface) - neck
6) thymus - mediastinum
7) adrenal glands - retroperitoneal abdominal cavity
8) pancreatic islets - pancreas
9) ovaries (females) - in pelvic cavity; testes (males) - scrotum
10) Placenta - pregnant uterus

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13
Q

Tropic hromones

A
  • hormones that target other endocrine glands and stimulate their growth/secretion
  • tend to stimulate synthesis and secretion of target hormone
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14
Q

sex hormones

A

hormones that target reproductive tissues

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15
Q

Anabolic hormones

A

hormones that stimulate anabolism in their target cells

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16
Q

How can hormones be classified?

A

1) by their general function
3) by their chemical structure - steroid and non-steroid homones

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17
Q

Characteristics of steroid hormone molecules

A
  • manufactured by endocrine cells from cholesterol (so all have characteristic chemical group at the core of each molecule)
  • lipid soluble = easily pass through the phospholipid plasma membrane of target cells
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18
Q

Name the 5 important steroid hormones

A
  • cortisol
  • aldosterone
  • estrogen
  • progesterone
  • testosterone
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19
Q

Characteristics of non-steroid hormones

A
  • synthesized primarily from AA rather than cholesterol
  • some are protein hormones (long, folded chains of AA)
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20
Q

Nonsteroid protein hormones (7)

A
  • GH
  • Prolactin
  • Parathyroid hormone (PTH)
  • Calcitonin (CT)
  • Adrenocorticotropic hormone (ACTH)
  • Insulin
  • Glucagon
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21
Q

Characteristics of glycoprotein hormones

A
  • nonsteroid hormones subgroup
  • they are protein hormones that have carbohydrate groups attached to their AA chains
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22
Q

Glycoprotein hormones (4)

A
  • Follicle-stimulating hormone (FSH)
  • Luteinizing hormone (LH)
  • Thyroid-stimnulating hormone (TSH)
  • Human chorionic gonadotropin (hCG)
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23
Q

Characteristics of peptide hormones

A
  • category of nonsteroid hormones
  • smaller than protein hormones, made of short chain AA
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24
Q

Name the main peptide hormones (7)

A
  • Antidiuretic hormone (ADH)
  • Oxytocin (OT)
  • Melanocyte-stimulating hormone (MSH)
  • Somatostatin (SS)
  • Thyrotropin-releating hormone (TRH)
  • Gonadotropin-releasing hormone (GnRH)
  • Atrial natriuretic hormone (ANH)
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25
Q

Characteristic of amino acid derivative hormones

A
  • category of nonsteroid hormones
  • derived from a single AA molecule
  • two major subgroups:
    • amine hormones - synthesized by modifying a single of either tyrosine or tryptophan
    • Iodinated AA: produced by the thyroid gland and synthesized by adding iodine (I) atom to the tyrosine molecule
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26
Q

Nonsteroid hormones: Amine hormones

A
  • NE
  • Epi
  • Melatonin
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27
Q

Non-steroid hormones: Iodinated AA (2)

A
  • thyroxine (T4)
  • Triiodothyronine (T3)
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28
Q

Define synergism

A

combination of hormones having a greater effect on a target cell than the sum of the effects that each would have if acing alone (basically enhancing each other’s influence when working together)

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29
Q

Define permissiveness re: combined hormone actions

A
  • phenomenon that occurs when a small amount of one hormone allows a second hormone to have its full effect on a target cell
  • the first hormone “permits” the full action of the second hormone
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30
Q

Define antagonism re: combined hormone actions

A
  • one hormone produces the opposite effect of another hormone
  • can be uesd to “fine-tune” the activity of target cells with great accuracy
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31
Q

Prolactin (PRL)

A
  • Primary action: regulate milk production (lactation) and reproduction
  • also has ~300 secondary actions in the body
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32
Q

Most secondary effects of hormones include what?

A

modulating/influencing the activity of other regulatory mechanisms (which is different than their primary effects which is a more direct regulatory mechanism)

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33
Q

What happens to unused hormone molecules?

A

quickly excreted by the kidneys or broken down by metabolic processes

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34
Q

Describe the process/mechanism of steroid hormones (i.e. how they get to where they need to go and have an effect on target cells)

A
  1. steroid hormones attach to soluble plasma proteins in the blood (because they’re lipids so not very soluble in blood plasma on its own)
  2. dissociates from its carrier before approaching target cell
  3. passes through phospholipid bilayer of target cell easily since lipid
  4. hormone enters nucleus and binds to mobile-receptor molecule, forms hormone-receptor complex
  5. hormone-receptor complex binds to specific gene location on nuclear DNA
  6. transcription of gene produces new mRNA strands
  7. new mRNA moves to cytosol where ribosome translates it into a protein
  8. new protein (enzyme or membrane transporter) produces specific effects in target cell
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35
Q

Mobile-receptor model/nuclear-receptor model

A

model of hormone action where steroid hormone receptors are not attached to the plasma membrane but instead move freely in the nucleoplasm

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36
Q

Does the amount of steroid hormone present determine the magnitude of a target cell’s response?

A

Yes

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37
Q

Responses to steroid hormones can take how long before the full effect is seen?

A

from 45 minutes to several days before the full effect is seen (because transcription and protein synthesis can take time)

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38
Q

Nonsteroid hormones typically operate according to a mechanism called

A

second messenger model

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39
Q

Second messenger model

A
  • aka fixed membrane receptor model
  • concept of signal transduction where a nonsteroid hormone acts as a”first messenger” delivering its chemical message to fixed receptors in the target cell’s plasma membrane
  • message is then passed into the cells “second messenger” triggering cellular changes
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40
Q

Describe how a nonsteroid hormone triggering a G protein-coupled receptor (GPCR) leads to cellular changes via the second messenger model.

A

1) nonsteroid hormone triggers a GPCR embedded in plasma membrane

2) activated GPCR causes integral membrane protein (G protein) to bind to guanosine triphosphate (GTP) which then acivates another membrane protein (adenyl cyclase)
3) adenyl cyclase promotes removal of two P groups from ATP leading to formation of cyclic adenosine monophosphate (cAMP)
4) cAMP acts as a second messenger in cell, activating other enzymes that activate additional enzymes to cause cellular changes

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41
Q

Describe how a nonsteroid hormone triggering opening of Ca+ channels leads to cellular changes (via second messenger model).

A

1) hormone binds to GPCR on membrane activating chain of integral membrane proteins (G protein and PIP2)
2) this triggers calcium channels to open in the plasma membrane
3) Ca++ enter cell and bind to calmodulin
4) Ca2+-calmodulin complex forms and acts as a second messenger to then influence enzymes that produce the target cell’s response

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42
Q

(Steroid/Nonsteroid) hormones are stored in secretory vesicles before release

A

nonsteroid

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43
Q

Response time of steroid vs nonsteroid hormones (i.e. time if takes for each to produce their full effects)

A

Steroid: 1 hour to several days

Nonsteroid: several seconds to a few minutes

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44
Q

Which of the following statements are true?

a) with nonsteroid hormones, cascade of reactions produced in second messenger mechanisms greatly amplifiy the effects of the hormone (i.e. the effect is greater than the amount of hormone present)
b) steroid hormones produce reactions that are greatly amplified (meaning the effects of the hormones are disproportionate when compared to the amount of hormone present)
c) second messenger mechanisms act a lot slower than steroid mechanisms
d) steroid hormones are stored in secretory vesicles before release

A

a)

with nonsteroid hormones, cascade of reactions produced in second messenger mechanisms greatly amplifiy the effects of the hormone (i.e. the effect is greater than the amount of hormone present)

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45
Q

Which of the nonsteroid hormones are exceptions by not operating via the second messenger model? What mechanism do follow instead to induce cellular changes?

A

thyrosine (T4)

Triiodothyronine (T3)

Mechanism: enter target cells and bind to receptors already associated with a DNA moelcule within the nucleus; forms hormone-receptor complex which triggers transcription of mRNA and synthesis of new enzymes (similar to steroid mechanism)

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46
Q

List 4 examples of secondary messengers

A

cAMP

inositol triphosphate (IP3)

cyclic guanosine monophosphate (cGMP)

calcium-calmodulin complex

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47
Q

During labour, muscle contractions become stronger and stronger to push the baby through birth canal via positive feedback loop that regulates secretion of which hormone?

A

oxytocin

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48
Q

How does PTH (parathyroid hormone) regulate calcium concentration in the blood during lactation?

A

During lactation in a breastfeeding woman, it consumes more Ca++ and therefore lowers [Ca2+] in the blood. Parathyroids sense this change and increase PTH secretion. PTH produces responses in its target cells that increase [Ca2+] in the blood (stimulating osteoclasts in bone to release more Ca2+ from storge in bone tissue to increase [Ca2+]; when blood [Ca2+] exceeds setpoint value, parathyroid cells can sense that and reflexively reduce their output of PTH

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49
Q

Secretion of hormones by the anterior pituitary can be regulared by releasing/inhibiting hormones secreted by what gland?

A

hypothalamus

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50
Q

Does the number of receptors a target cell has for that hormone affect its sensitivity to that hormone?

A

YES. These hormone receptors are also constantly broken down by the cell and replaced with newly synthesized receptors to allow for new cell parts as well as the number of receptors to be changed from time to time

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51
Q

Define upregulation

A

when the number of receptors being newly synthesized are done at a faster rate than those degraded in the target cells causing the cell to be more sensitive to the hormone

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52
Q

Define downregulation

A

If the rate of receptor degradation exceeds rate of receptor synthesis, then the number of receptors will decrease thus sensitivity to the hormone also goes down

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53
Q

Various endocrine disorders that result from hyposecretion of hormones are actually due to what?

A
  • the target cell have damaged receptors, too few receptors, or abnormality reuslting in an improper response to that hormone
  • therefore lack of target response could be a sign of hyposecretion or a sign of target cell insensitivity
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54
Q

Eicodanoids/Icosanoids

A
  • unique group of lipid molecules that serve important and widespread integrative functions in the body but don’t meet the usual definition of a hormone
  • described as tissue hormone because secretion is produced in a tissue and diffuses only a short distance to other cells within the same tissue
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55
Q

Eicosanoids include which three molecules?

A

prostaglandins (PGs)

thromboxanes

leukotrienes

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56
Q

Describe: prostaglandin

Source

Target

Principal action

A

Source: many diverse tissues of the body

Target: local cells within source tissue

Principal action: diverse local effects (regulating inflammation, muscle contraction in blood vessels)

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57
Q

Describe: Thromboxanes

Source

Target

Principal action

A

Source: platelets

Target: other platelets; muscles in blood vessel walls

Principal Action: increase stickiness of platelets; promote blood clotting; cause constriction of blood vessels

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58
Q

Describe: Leukotrienes

Source

Target

Principal action

A

Source: several types of leukocytes

Target: local cells of various types

Principal Action: produce local inflammatory responses triggered by allergens (airway constriction in asthma) and other inflammatory responses

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59
Q

Definition of “endocrine hormone”

A

hormones that are secreted from a tissue into the bloodstream and have their effects in target cells at some distance from their source

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60
Q

Paracrine hormones

A

hormones that regulate activity in nearby cells within the same tissue as their source (Local hormone)

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61
Q

Autocrine hormones

A

hormones that regulate activity in the secreting cell itself

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62
Q

Describe the structure of eicosanoids

A
  • 20-carbon unsaturated FA and contain a 5-carbon ring
  • made by cells breaking apart membrane phospholipids and using their FA tails
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63
Q

How many different prostaglandins are there and how many structure classes?

A

16 different PGs, falling into 9 different structural classes (PGA through PGI)

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64
Q

Intraarterial infusion of PGAs result in:

A

immediate fall in BP with increased in regional blood flow to several areas (coronary and renal systems); caused by relaxation of smooth muscle fibers in the walls of certain arteries and arterioles

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65
Q

Prostaglandin E (PGEs) role

A
  • Vascular functions: regulation of RBC deformability and platelet aggregation; systemic inflammation (like fever)
    • can be blocked with drugs (ASA, ibuprofen) that inhibit PG-producing enzymes such as COX-1 and COX-2
  • metabolic and GI functions
    • regulates HCl secretion in the stomach to prevent gastric ulcers
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66
Q

Prostaglandin F (PGFs) role

A
  • reproductive system: causes uterine muscle contractions (helps with inducing labour and accelerating delivery of a baby)
  • also affects intestional motility and required for normal peristalsis
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67
Q

Thromboxane A2

A
  • a regulator synthesized by blood platelets, needed for blood clotting
  • aspirin targets the synthesis of thromboxane A2
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68
Q

Leukotrienes

A

regulators of immunity

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69
Q

Pituitary adenomas are benign tumors that can cause (hyper/hypopituitarism).

Larger tumors on the pituitary gland can lead to possible outcomes of ___________.

A

hyperpituitarism

Larger tumros can lead to hyperpituitarism with gigantism (acromegaly)

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70
Q

Common causes of hypersecretion of hormones

A
  • tumors
  • autoimmunity
  • faillure of feedback mechanisms that regulate secretion of a hormone
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71
Q

Graves disease

A
  • autoimmune disorder where autoimmune antibodies against TSH receptor stimulate the receptor and mimic the activity of TSH
  • causes thyroid gland to hypertrophy and excess thyroid hormone to be produced
  • Sx: unexplained weight loss, nervousness, increased HR, exophthalmos (bulging eyes)
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72
Q

Primary hyperparathyroidism

A

condition characterized by failure of the parathyroid gland to adjust its output to compensate for changes in blood calcium levels (thus overproduces PTH)

73
Q

Potential causes of hyposecretion

A

1) tumors
2) tissue death (from blockage or other failure of blood supply to the gland)
3) abnormal operation of regulatory feedback loops
4) abnormalities of immune function
5) insensitivity of target cells to tropic hormones rather than hyposecretion

74
Q

How do anabolic steroids cause hyposecretion of testoterone and gonadotropic hormones?

A
  • steroids increase their blood concentration of testosterone above their set point values
  • desired effect is to promote muscle growth and increased strength but body responds to shi overabundance by reducing own output of testosterone which causes sterility and other complications
75
Q

Pituitary Gland - Structure

A
  • aka hypophysis cerebri
  • master gland

Structure: small structure (1.2-1.5 cm, weights 0.5g) that’s well protected within the skull on ventral surface of brain

  • lies in pituitary fossa of sella turcica
  • covered by portion of dura mater called pituitary diaphgram
  • has a stemlike stalk (infundibulum) connecting it to hypothalamus
  • actually TWO glands: adenohypophysis and neurohypophysis
76
Q

The pituitary gland is made up of two separate glands. What are they and how are they different?

A

Adenohypophysis: anterior pituitary gland

  • develops from an upward projection of the pharynx and composed of regular endocrine tissue

Neurohypophysis: posterior pituitary gland

  • develops from downward projection of the brain, composed of neurosecretory tissue
77
Q

Structure of adenohypophysis

A
  • divided into two parts:
    • par anterior - forms the major portion of the gland and divded from pars intermedia by a narrow cleft and some connective tissue
    • pars intermedia
  • composed of irregular clumps of secretory cells supported by fine connective tissue fibers and rich vascular network
78
Q

What are the 5 classifications of cells of the adenohypophysis that are classified by their secretions?

A

1) Somatotrophs - secrete growth hormone (GH)

2) Corticotrophs - secrete adrenocorticotropic hormone (ACTH)

3) Thyrotrophs - secrete thyroid-stimulating hormone (TSH)

4) Lactotrophs - secrete prolactin (PRL)

5) Gonadotrophs - secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH)

79
Q

Growth hormone (GH)

A
  • aka somatotropin (STH) or human growth hormone (HGH)
  • promotes bodily growth (bone, muscle, tissue) indirectly by stimulating liver and other tissues to produce insulin-like growth factor 1 (IGF-1) which then produces most of the effects
  • accelerates AA transport into the cells (via IGF-1) which increases protein anabolism = increased rate of growth
  • stimulates fat metabolism, accelerates lipid mobilization from storage, speeds up catabolism of lipids
  • basically shifting cell use away from carb catabolism and toward lipid catabolism, increases blood sugar levels
80
Q

Gigantism

A
  • Hypersecretion of GH during growth years (before ossification of epiphyseal plate) causes rapid skeletal growth
  • leads to acromegaly (when cartilage still left in the skeleton continues to form new bone)
  • may result in distorted appearance due to enlargement of hands, feet, face, jaw (causing teeth separation), etc.
  • skin often thickens and pores become more pronounced
81
Q

Pituitary dwarfism

A

hyposecretion of GH during growth years leading to stunted body growth

82
Q

Why would GH have a hyperglycemic effect? What hormone would have the opposite effect?

A
  • Because it promotes lipid breakdown as energy use instead of carbs (glucose) so there is less glucose being removed from the blood by cells
  • Opposite effect: insulin (which promotes glucose entry into cells)
  • GH and insulin therefore are antagonists
83
Q

Prolactin (PRL)

A
  • aka lactogenic hormone
  • produced by acidophils in pars anterior
  • generating/initiating milk secretion (lactation) - so high levels of PRL promote development of breasts in anticipation of milk secretion
  • TARGET: mammary glands
  • When baby is delivered, PRL in mother stimulates mammary glands to begin milk secretion
84
Q

Prolactinoma

A
  • noncancerous adenoma that produces hypersecretion of PRL
  • small and mostly occur in women
  • Sx: headache, vision and sensory changes, lethargy
  • excess PRL leads to breast tenderness/enlargement, abnormal milk production, infertility, and loss of sexual interest/function
85
Q

The four principle tropic hormones are what and where are they produced and secreted from?

A
  • produced and secreted by basophils of pars anterior
  • Thyroid-stimulating hormone (TSH)
  • Adrenocorticotropic hormone (ACTH)
  • Follicle-stimulating hormone (FSH)
  • Luteinizing hormone (LH)
86
Q

Adrenocorticotrophic hormone (ACTH)

A
  • aka adrenocorticotropin
  • promotes and maintains normal growth and development of adrenal cortex
  • also stimulates adrenal cortex to synthesize and secrete some of its hormones
87
Q

Thyroid-stimulating hormone (TSH)

A
  • aka thyrotropin
  • promotes and maintains growth and development of the thyroid
  • causes thyroid gland to secrete thyroid hormone
88
Q

Follicle-stimulating hormone (FSH)

A
  • stimnulates structures within the ovaries, primary follicles, to grow toward maturity
  • each follicle contains a developing egg cell (fovum) which is released from ovary during ovulation
  • FEMALES: also stimulates follicle cells to synthesize and secrete estrogens (female sex hormones)
  • MALES: stimulates development of seminiferous tubules of testes and maintains sperm production by them
89
Q

Luteinizing hormone (LH)

A
  • stimulates formation and activity of corpus luteum of the ovary (aka the tissue left behind when a follicle ruptures to release its egg during ovulation)
  • corpus leuteum secretes progesterone and estrogens when stimulated by LH
  • also supports FSH in stimulating maturation of follicles
  • in males, LH stimulates intersitial cells in the testes to develop and then synthesize and secrete testosterone
90
Q

Gonadotropins - what are they

A
  • include FSH and LH because they stimulate growth and maintenance of gonads (ovaries and testes)
  • minimal amounts secreted by adenohypophysis in childhood but then gonadotropin secretion gradually increases a few years before puberty (and then secretion spurts
91
Q

Chemicals called releasing hormones are synthesized and released from hypothalamus to the adenohypophysis through what vasculature?

A

hypophyseal portal system (carries blood from hypothalamus directly to the adenohypophysis)

92
Q

What is the advantage of the hypophyseal portal system?

A
  • that a small amount of hormone can be delivered directly to its target tissue without great dilution that would typically occur in the general circulation
93
Q

What hormones are secreted by the hypothalamus into the hypophyseal portal system?

A
  • Growth hormone-releasing hormone (GHRH) - stimulates release of GH
  • Growth hormone-inhibiting hormone (GHIH) - also called somatostatin (SS), inhibits GH secretion
  • Corticotropin-releasing hormone (CRH) - stimualtes release of ACTH
  • Thyrotropin-releasing hormone (TRH) - stimulates release of TSH
  • Gonadotropin-releasing hormone (GnRH) - stimulates release of FSH and LH
  • Prolactin-releasing hormone (PRH) - stimulates release of prolactin
  • Prolactin-inhibiting hormone (PIH) - inhibits release of prolactin
94
Q

GHRH secretion by the hypothalamus peaks during what time of the day?

A

during sleep

95
Q

The frequency of GHRH spikes (increased secretion by the hypothalamus) can be due to what factors?

A

exercise, stress, and high protein meals

96
Q

The mind-body link is provided through which gland?

A

hypothalamus (meaning that hypothalamus can receive nerve impulses and translate it into hormone secretion by endocrine glands)

97
Q

Neurohypophysis

A
  • posterior lobe of pituitary
  • serves as a storage and release site for ADH and oxytocin (OT)
  • the cells of neurohypophysis do not themselves make these hormones but instead neurons whos bodies are in either the supraoptic or paraventricular nuclei of the hypothalamus synthesize them
    • for these hormones, they go from hypothalamus to neurohypophysis via hypothalamohypophyseal tract
98
Q

ADH and OT release into the blood is controlled by

a) nervous stimulation
b) chemical releasing factors that trigger their secretion
c) can be triggered by nervous stimulation and chemical releasing factors
d) neither

A

a) nervous stimulation

99
Q

ADH

A
  • prevents formation of large volume of urine (water conservation) - to maintain water balance in the body
  • target gland: kidney
100
Q

When the body dehydrates, how does the body sense that ADH needs to be released? Describe the physiological process.

A

1) body dehydrates, osmotic pressure of blood increases
2) increased pressure is detected by osmoreceptors near supraoptic nucleus
3) triggers release of ADH from neurohypophysis
4) ADH causes water to be reabsorbed from kidney tubules and returned to the blood
5) water content in blood increases restoring osmoting pressure to normal lower level

101
Q

Beside water balance and regulation by ADH, what other functions/effects does it have on the body?

A

stimulates muscle contraction in the walls of small arteries to increase BP (that’s why ADH is also known as vasopressin)

102
Q

Hyposecretion of ADH can lead to what condition and how can this alleviated?

A
  • diabetes insipidus (condition where patient produces abnormally large amounts of urine)
  • desmopressin and related drugs mimic ADH and can alleviate this sx
103
Q

Lost the two primary actions of oxytocin as well as two additional actions/functions.

A

Primary actions:

1) stimulates rhythmic contraction of smooth muscles in the uterus
2) causes milk ejection from the breasts of lactating women

Other functions/actions:

1) maintaining skeletal muscle regeneration

involved in social bonding

104
Q

How does oxytocin stimulate milk ejection from lactating breasts? Furthermore, what action causes release of more OT?

A
  • myoepithelial cells surround the alveoli of mammary glands (where milk is stored) and these cells squeeze milk into the ducts of the breast
  • this squeezing is required because they need to be ejected into the ducts before suckling can actually get milk out
  • MORE OT is released by the mechanical and physiological stimulation of the baby’s suckling action
105
Q

How is release of OT a positive feedback mechanism?

A
  • baby suckles which increases OT levels
  • provides more milk
  • baby continues to suckle which continues to increase OT levels and so on
106
Q

What are the two hormones that ensure successful nursing in a lactating individual?

A

oxytocin and PRL

PRL: prepares breast for milk production and stimulates cells to produce milk

Oxytocin: stimulates release of milk

107
Q

Discuss how OT release during labour is a positive feedback mechanism?

A

1) OT stimulates uterus to strengthen the strong muscle labor contractions that occur during childbirth
2) uterine contractions stimulate stretch receptors in the pelvis, triggers release of more OT
3) more OT triggers stronger muscle contractions = stretches pelvic receptors more, etc.

108
Q

Oxytocin (rises/falls/stays the same) during sexual arousal in both males and females.

A

Rises - increased OT allows for smooth muscle contractions associated with sexual arousal and orgasm

109
Q

True or False. Oxytocin also has an effect on skeletal muscle (not just smooth muscle), specifically by supporting normal muscle regeneration

A

True (therefore some of the loss of skeletal muscle mass in aging may be due to reduced secretion of OT as we age)

110
Q

Oxytocin target glands/tissues

A

uterus and mammary glands

111
Q

Structure and function of pineal gland

A

Structure: small pine nut-like gland located on dorsal aspect of brain’s diencephalon region

Function: acts as a part of both nervous and endocrine system (because it receives and processes nerve stimuli from other parts of NS and secretes hormones)

  • produces small amounts of diff hormones but principle hormone is melatonin
112
Q

Melatonin levels (rise/fall/stay the same) when sunlight is absent, and (rise/fall/stay the same) when sunlight is present

A

rise (triggering sleepiness at nighttime)

fall (allowing us to be alert during daytime)

113
Q

Why would melatonin affect someone’s mood?

A

because it’s associated with serotonin which is a mood-altering molecule (serotonin is a precursor of melatonin)

114
Q

Structure of the thyroid gland

A
  • made up of two large lateral lobes and narrow isthmus connecting the two lobes together
  • also has a thin “worm-like” piece of thyroid tissue (paramidal lobe) that extends upward from the isthmus
  • weighs ~30g
  • located in the neck on anterior and lateral surfaces of the trachea just below the larynx
115
Q

Synthesis of thyroid hormone (TH) happens where in the thyroid gland?

A
  • in tiny structure units called follicles in the thyroid tissue
  • each follicle is a small hollow sphere with a wall made of cuboidal glandular epithelium, interior filled with thyroid colloid fluid (which is produced by the cuboidal cells from the walls and contains thyroglobulins- precursors of THs)
116
Q

Thyroglobulins

A

precursors of TH, contain protein-iodine complexes

117
Q

Calcitonin is produced by what?

A
  • parafollicular cells called C cells which are found around the outside of follicles in the thyroid gland
118
Q

Thyroid hormone (TH) is actually two different hormones. What are they?

A
  • tetraiodothyronine (T4) or thyroxine - most abundant
    • contains 4 iodine atoms
    • a precursor to T3
  • triiodothyronine (T3)
    • ​contains 3 iodine atoms
119
Q

Which of the endocrine glands stores its hormones in another form before secreting them at a later time?

A

thyroid gland

120
Q

How are T3 and T4 transported in the bloodstream?

A

attached to plasma proteins (a thyroid-binding globulin and albumin) to travel around as a hormone-globulin complex

121
Q

(T4/T3) is the most abundant TH.

(T4/T3) is the most potent TH. Why?

A

Most abundant: T4 - thyroid gland releases ~20x more T4 than T3

Most potent: T3 - considered the “principal TH”

  • T4 binds more strongly to plasma globulins than T3 so T4 is not removed from the blood by target cells as quickly as T3
  • also T3 binds more efficiently than T4 to nuclear receptors in target cells
122
Q

Function of TH

A

help regulate metabolic rate of all cells as well as processes of cell growth and tissue differentiation

123
Q

Cretinism

A
  • condition caused by hyposecretion of TH during growth years
  • characteized by low metabolic rate, retarded growth and sexual development, and possibly intellectual disability
  • profound manifestations of this condition lead to deformed dwarfism (diff than proportional dwarfism caused by hyposecretion of GH)
124
Q

Myxedema

A
  • swelling and firmness of skin caused by accumulation of mucopolysaccharides in the skin (advanced hypothyroidism)
125
Q

A simple goiter is when the thyroid enlarges and can be caused by a lack of what substance in the diet?

A

iodine

126
Q

Lack of iodine in the diet results in a(n) (increase/decrease) in secretion of thyrotropin-releasing hormone (TRH) and thyroid-stimulating hormone (TSH)

A

increases (in an attempt to stimulate thyroid to produce more thyroid hormone but because there is no iodine available, the gland itself enlarges)

127
Q

Calcitonin (CT) is involved in what functions?

A
  • processing of calcium by bone cells
  • control calcium content of the blood by increasing bone formation by osteoblasts and inhibiting bone breakdown by osteoclasts
    • meaning more calcium is removed from blood by the osteoblasts and less calcium is released into the blood by osteoclasts
128
Q

The antagonist of calcitonin is

A

parathyroid hormone (PTH)

129
Q

What two main hormones maintain calcium homeostasis?

A

calcitonin and PTH

130
Q

How many parathyroid glands are embeeded in the posterior surface of the thyroid’s lateral lobes? What do they look like?

A

4-5; looks like tiny rounded bodies within thyroid tissue formed by compact, irregular rows of cells

131
Q

PTH function and target organs/tissues

A
  • PTH acts on bone and kidney cells by increasing release of calcium into the blood
  • in bones, it causes less new bone to be formed and more old bone to be dissolved (to yield calcium and phosphate)
  • increases blood levels of calcium and phosphate
  • in kidneys, only calcium is reabsorbed from urine into the blood; phsophate is excreted via urine
132
Q

Which hormone increases the body’s absorption of calcium from food by activating vitamin D?

A

PTH (vitamin D is convered to active hormone calcitrol in the kidney which permits Ca2+ to be transported through intestinal cells and into the blood

133
Q

Which of the following rely on the maintenance of calcium homeostasis?

a) normal neuromuscular excitability
b) blood clotting
c) cell membrane permeability
d) normal functioning of other enzymes
e) all the above

A

e) all the above

134
Q

Structure and Location of adrenal glands

A
  • located on top of the kidneys
  • adrenal cortex: outer portion of adrenal gland; made of endocrine tissue
  • adrenal medulla: inner portion of adrenal gland; made of neurosecretory tissue
  • both^ synthesize and secrete a different set of hormones
135
Q

What are the three regions that make up the adrenal cortex, and what hormones does each secrete?

A

1) Zona glomerulosa - mineralocorticoids (aldosterone)

2) Zona fasciculata - glucocorticoids (cortisol)

3) Zona reitcularis - small amounts of sex hormones (gonadocorticoids: androgens, estrogens) and glucocorticoids

136
Q

Aldosterone

A
  • mineralocorticoid
  • Function: maintain sodium homeostasis in the blood; also promotes water retention because water follows sodium
  • Process: increasing sodium reabsorption in the kidneys (back into the blood in exchange for K+ or H+ ions) - so it also influences K+ and pH levels in blood
  • Controlled by: RAAS and [K+] in blood
137
Q

Describe the action of RAAS when blood pressure in the kidneys drop below a certain level

A

1) juxtaglomerular apparatus secretes renin into the blood
2) renin causes angiotensinogen to be converted to angiotensin I
3) Angiotensin I circulates through bloodstream and gets converted into Angiotensin II via ACE (mostly in the lungs)
4) Angiotensin II circulates to adrenal cortex to stimulate aldosterone secretion
5) Aldosterone causes increased reabsorption of sodium which causes increased water retention
6) Water retention leads to increased blood volume = higher BP
7) RAAS stops (-ve feedback loop)

138
Q

The chief glucocorticoids secreted by zona fasciculata of adrenal cortex is

A

cortisol (or hydrocortisone)

cortisone

corticosterone

139
Q

Functions of glucocorticoids

A

1) protein mobilizing, gluconeogenic, hyperglycemic

  • accelerates protein breakdown in AA (except in liver cells) to mobilize AA
  • AA circulates to liver cells and changes to glucose (via gluconeogenesis)
  • prolonged high concentrations of glucocorticoids cause hyperglycemia because of all the AA being changed to glucose

2) lipid mobilization and catabolism

  • accelerates mobilization of lipids from adipose cells and catabolism of lipids (shifting from carb breakdown to lipid breakdown as energy source)
  • may be used in liver for gluconeogenesis so also contributes to hyperglycemia

3) Maintaining normal BP - permits NE and Epi to vasoconstrict; prolonged high concentrations may lead to HTN

4) Quick increase in glucocorticoids in blood leads to decrease in immunity

  • eosinophils are decreased, lymphatic tissues atrophy (especially thymus gland and lymph nodes) which decreases lymphocytes/plasma cells in the blood = antibody formation decreases, leading to less defence against infection

5) Return to normal recovery from injury produced by inflammatory agents - normal amounts of glucocorticoids and Epi

6) Involved in stress response - increased glucocorticoid secretion allows increase in glucose available for muscles needing it in fight or flight responses (but prolonged stress leads to immune dysfunction)

140
Q

Glucocorticoid secretion is controlled mainly be means of -ve feedback mechanism that involves what hormone?

A

adrenocorticotropic hormone (ACTH)

141
Q

Cushing syndrome

A
  • A collection of symptoms that result from hypersecretion of cortisol from the adrenal cortex
  • body fat gets redistributed leading to “moon face” and thin reddened skin
142
Q

Aldosteronism

A

hypersecretion of aldosterone leading to increased water retention and muscle weakness resulting from K+ loss

143
Q

Hypersecretion of androgens can result from tumors of the adrenal cortex called

A

virilizing tumors

144
Q

Addison disease

A
  • hyposecretion of mineralocorticoids and glucocorticoids
  • may lead to a drop in blood sodium and blood glucose, increase in blood potassium levels, dehydration, and weight loss
  • hyperpigmentation
145
Q

Which of the following is false about adrenal medulla?

a) composed of neurosecretory tissue
b) innervated by sympathetic preganglionic fibers of the ANS
c) secretes catecholamines
d) secretes steroid hormones

A

d) secretes steroid hormones - this is false

146
Q

What are the two nosteroid hormones in the category of catecholamines secreted by adrenal medulla?

A

epi (80% of medulla’s secretion) and NE (20% of medulla’s secretion)

147
Q

Structure of pancreas

A
  • elongated gland
  • head of the gland lies in C-shaped beginning of duodenum
  • body extends horizontally behind the stomach and tail touching spleen
  • composed of endocrine and exocrine tissue
148
Q

Structure of pancreatic islets

A
  • aka islets of Langerhans
  • makes up the endocrine portion of the pancreas in little scattered tiny islands of cells (account for ~2-3% of total mass of pancreas)
  • each islet contains 4 (5?) primary types of endocrine cells, joined via gap junctions
    • alpha cells - secretes glucagon
    • beta cells - secretes insulin (account for ~3/4 of all pancreatic islet cells)
    • delta cells - secrete hormone SS
    • pancreatic polypeptide cells - secrete PP
    • epsilon cells - secrete ghrelin (GHRL)
149
Q

Glucagon is produced by what cells and what is its function

A
  • produced by alpha cells
  • increases blood glucose levels by stimulating conversion of glycogen to glucose in liver cells
  • also stimulates gluconeogenesis (transformation of FA and AA into glucose) in liver cells
  • hyperglycemic effect
150
Q

Insulin - produced by what cells, what is its function

A
  • produced by beta cells
  • promotes uptake of glucose, AA, and FA into tissue cells so lowers blood concentration of these while promoting metabolism by tissue cells
151
Q

Somatostatin - produced by what cells and what is its function

A
  • produced by delta cells in pancreas
  • primary role: regulating other endocrine cells of pancreatic islets
  • inhibits secretion of glucagon, insulin, and pancreatic polypeptide (PP)
  • also inhibits secretion of GH (somatotropin or STH) from anterior pituitary
152
Q

Pancreatic polypeptide (PP) - produced by what cells, what is its function

A
  • produced by PP cells (F cells) in periphery of pancreatic islets
  • influences GI motility, secretion by exocrine pancreas, and feelings of hunger/satiety
153
Q

Ghrelin - produced by what cells, what is its function

A
  • produced in tiny amounts by epsilon cells near outer boundary of pancreatic islets; also secreted by gastric mucosa
  • stimulates hypothalamus to boost appetite
  • also acts on other body tissues to slow metabolism and reduce fat burning (so may have contributing to obesity)
154
Q

Gonads

A

the primary sex organs (testes in males, ovaries in females)

155
Q

Testes - structure and function

A

Structure: paired organs within sac of skin (scrotum) which hang from groin area of trunk

  • composed mainly of coils of sperm-producing seminiferous tubules, and around that is endocrine interstitial cells

Function:

  • interstitial cells produce androgens (principal androgen - testosterone)
156
Q

Testosterone function

A
  • responsible for growth and maintenance of male sex characteristics
  • sperm production
  • testosterone secretion regulated by gonadotropin (especially LH) levels in the blood
157
Q

Ovaries - structures

A
  • set of paired glands in the pelvis that produce several types of sex hormones (estrogen, progesterone)
  • regulation ovarian hormone secretion is dependent on changing levels of FSH and LH from adenohypophysis
158
Q

Estrogen - Secreted by what cells, function

A
  • includes estradiol and estrone
  • steroid hormones that are secreted by ovarian follicles
  • promotes development and maintenance of female sex characteristics
  • also involved in breast development and menstrual cycle
159
Q

Progesterone - Secreted by what and what is this hormone’s function

A
  • the “pregnancy-promoting steroid”
  • secreted by corpus luteum
  • maintains the lining of uterus necessary for gestation
160
Q

Placenta

A
  • tissue that forms on the lining of the uterus and acts as an interface between circulatory systems between mom and fetus
  • a temporary endocrine gland
161
Q

The placenta produces what hormones?

A

human chorionic gonadotropin (hCG)

human placental lactogen (hPL)

relaxin

162
Q

Human Chorionic Gonadotropin (hCG)

A
  • secreted by the chorion (fetal tissue component of the placenta)
  • stimulates development and hormone secretion by maternal ovarian tissues
  • secretion is high during early part of pregnancy (to cue mother’s gonads to maintain uterine lining instead of shedding it away such as in menstruation)
  • production of hCG drops when estrogen and progesterone production increases (After first trimester)
163
Q

Thymus

A
  • gland in mediatstinum just beneath sternum
  • large in children until puberty then atrophies throughout adulthood
  • because adipose tissue by old age
164
Q

Two major hormones secreted by the thymus gland

A
  • thymosin
  • thymopoietin
165
Q

Role of thymosin and thymopoietin

A

involved in stimulating production of T cells (involved in immune system)

166
Q

GI hormones include what hormones and what is their overall function?

A

gastrin

secretin

cholecystokinin (CCK)

Function: regulatory role sin coordinating secretory and motor activities involved in digestive process

167
Q

Secretin - Role

A
  • released when acids make contact with intestinal mucosa
  • carried by blood triggering its target cells in the stomach to reduce acid secretion
  • also triggers target cells in pancreas to release alkaline fluid
  • acts with CCK to trigger pancreas to release digestive enzymes
168
Q

Cholecystokinin (CCK) - Role

A

triggers gallbladder to release more bile which helps break up fat droplets

169
Q

Heart’s secondary endocrine role involves which set of hormones?

A

atrial natriutretic peptides (ANP)

170
Q

Atrial Natriuretic Hormone (ANH)

A
  • secreted by atrium
  • secretion of ANH increases with increase in stretch of atrial wall caused by abnormally high blood volume/BP
  • promotes loss of sodium so water goes with it (overall reduces blood volume and thus decrease BP)
171
Q

Leptin is secreted by which organ/tissue, and what is its role?

A
  • adipose tissue
  • protein hormone involved in energy balance, regulation of immunity and neuroendocrine function, and development
  • stimulates GnRH release from hypothalamus (So some effect on reproductive function)
  • may reduce/stop menstruation in women who are starving or overexercising
172
Q

Resistin is secreted by which organs/tissues and what is its role?

A
  • secreted by adipose tissue and macrophages
  • reduces sensitivity to insulin and thus raises BGL
173
Q

Inhibin

A

hormone produced by ovaries, helps regulate FSH levels in women

174
Q

hormones produced by muscle tissues are called

A

myokines

175
Q

Irisin

A

hormone produced by muscle tissues and converts white fat into brown fat

176
Q

IL-6

A

produced by muscle tissues (myokines) and functions to signal liver to release glucose during prolonged exercise

177
Q

The principal organs of the urinary system are __________ and their function is to ______________.

A

kidneys; function is to process blood and form urine as a waste to be excreted (chief function to regulate volume and composition of body fluids and excrete unwanted material)

178
Q

Accessory organs of the urinary system include:

A

ureters, urinary bladder, and urethra

179
Q

Describe what each of the following system gets rid of through their excretion.

1) Urinary

2) Integumentary

3) Respiratory

4) Digestive

A

OCHT Term II (31 decks)

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